Ferrocement

Ferrocement is a thin-shell composite material made from a dense matrix of cement mortar reinforced with closely spaced layers of steel mesh or small-diameter rod, distinct from ordinary reinforced concrete in the much finer, more evenly distributed reinforcement and the resulting thinness, often under two inches, that a ferrocement shell can achieve while remaining strong and crack-resistant. Developed and named in the mid-nineteenth century and refined through the twentieth, notably by the Italian engineer Pier Luigi Nervi for thin-shell roof structures and boat hulls, it allowed architects and engineers to build lightweight, complex curved forms, including domes and vaults, with far less material and weight than conventional reinforced concrete construction.